ST. LOUIS, Missouri (CNN) -- At first blush, tonight's second presidential debate in the "Show Me State" should not shake up the race.

Earlier town hall debates, such as the one Friday night, have resulted in 4- and 8-percentage point poll swings -- in 1992 and 2000 respectively. Despite that, this closely fought battle will probably leave the polls relatively knotted.

That's not only because it was a close debate -- it also may be that Major League Baseball playoffs and other Friday night factors meant fewer people watched than expected.

Like the vice presidential candidates on Tuesday night, President Bush and John Kerry were each aggressive from the very outset as they handled a wide range of questions from environmental policy to Iran.

President Bush most likely kept his base strong answering "social values" questions about abortion and stem cell research. He also likely scored points with some conservatives with his challenge of John Kerry's record on taxes.

The president's unequivocal ruling out of a military draft probably helped him to some extent (at least in the short term) with women voters who, polls show, fear the possible reinstatement of a draft more than men.

But contrary to popular expectations, I thought Kerry scored his best points during the foreign policy discussion and overall won the first hour of the debate.

Kerry comfortably weaved policy arguments, statistics and historical references to make his point that he would have approached war with Iraq as well as relations with North Korea, Iran and other nations differently.

On domestic issues, he probably scored big political points on the importation of less expensive prescription drugs and his pledge not to raise taxes.

Although Kerry seemed to narrowly win the debate (securing his second debate win in a row), enough good things on Bush's part -- including a tough, philosophical style in discussing the war on terror -- means the polls are unlikely to change significantly based on the 90 minutes in St. Louis.

On the other hand, as both sides leave Missouri, the political "spin game" over the next 72 hours could produce a swing -- perhaps more like the modest 4-point swing following the 1992 town hall debate. Three interesting things could influence this debate's spin game:

Any major factual errors made by Kerry or Bush, like the one Vice President Cheney made on Tuesday about never meeting John Edwards;

A popular one-liner that gets adopted by local news programs and comics (e.g., "You can run but you can't hide"); and

The Sunday talk shows, which instead of just reporting the spin winner as they did last week, will probably hash out who won themselves. After all, no weekday news cycle followed Friday night.

The debate did underscore that several smaller issues could ultimately sway voters on the fence in one direction or another as Election Day nears -- the possibility of a draft, the Patriot Act and Supreme Court appointments.

And if John Kerry is ultimately judged the winner, the debate could help him revive his moribund Missouri campaign, given all of the free publicity that the debate offered both candidates.